Machine for producing gears



MACHINE FOR PRODUCING GEARS Filed April 6, 1932 11 Shets-Sheet 1 I INYENTOR @azrzd msera Y izzls ATTORNE July 28, 1936. i2. FINSEN 2,043,690

MACHINE FOR PRODUCING GEARS- I Filed April 6,.1932 11 Sheets-Sheet 2 INVENTOR aired Fizasek/ /mrjv Zia ATTORN July 28, 1936. E. FINSEN 2,948,590

MACHINE FOR PRODUCING GEARS I,

Filed April 6, 1952 11 Sheets-Sheet 3 INV ENTOR' 29mm: Izrzserb BY Zz's Anemia 6 July 28, 1936. E FINSEN 2,048,690

MACHINE FOR PRODUCING GEARS Filed April 6, 1932 ll Sheets-Sheet 4 INVENTOR Rnseza BY July 28,1936. E, HNSE 2,048,690

MACHINE FOR PRODUCING GEARS Filed April 6, 1932 ll SheetsShee+. 5

INV ENTOR E azrzci/ 1 2725676 BY iz's ATTORNEW July 28, 1936.

Filed April 6, 1932 E. FINSEN MACHINE FOR PRODUCING GEARS 11 SheetS-Sheet- 6 1&5 56

INVENTOR C [yaw vzs kz's ATTORNEY July 28, 1936. FlNsEN 2,048,690

MACHINE FOR PRODUCING GEARS Filed April 6, 1932 11 Sheets-Sheefl 7 INVENTOR I z/z'naz Mam his ATTORNE July 28, 1936. v E. FINSENY 2,048,690

MACHINE FOR PRODUCING GEARS Filed April 6, 1952 11 Sheets-Sheet 8 INYENTOR I lfyz/mci F-Znsera BY Zz's ATTORNEKV July 28', 1936. E. 'FINSEN 4 MACHINE-FOR PRODUCING GEARS Filed April 6, 1932 11 Sheets-Sheet 1O zls TTORNEY? July 28, 1936. E. FINSEN 2,048,690

MACHINE FOR PRODUCING GEARS I Filed April 6, 1952 11 Sheets-Sheet 11 INVENTOR Z255 ATTORNEY/7PM Patented July 28, 1936 UNITED STATES PATENT OFFICE MACHINE FOR. PRODUCING GEARS Eyvind Finsen, Rochester, N.. Y., assignor to Gleason Works, Rochester, N. Y., a corporation of New York Application April 6, 1932, Serial No. 603,541 14 Claims. (Cl.'51-52) The present invention relates to machines for producing gears and particularly to machines for generating bevel gears. In astill more specific aspect, the invention relates to machines for grinding straight beveled gears.

For years, machines have been used for generating bevel gears in which the generating roll is produced by oscillation of a cradle upon which the work or tool mechanism is mounted and by simultaneous rotation of the work through operation of a pair of segments, one of which is connected to the work spindle and the other of which has a fixed relation to the tool mechanism. These machines' have had the advantage of extreme simplicity in construction, and, therefore, of low cost. As built, heretofore, however, they have been suitable only for production work where the quantity of gears to be cut was sufiiciently large to allow the machine to be operated in- .definitely on one particular job, for, in these machines, change of a job has meant change of the cams for producing the feed and generating motions and either change requires time; moreover,-

the cams are expensive.

One object of the present invention is to provide a machine which, while preserving the characteristic simplicity of the prior machines referred to, will be capable of more nearly universal use. To this end, it is a purpose of the invention to provide a machine in which the amount of feed movement is capable of infinite variation within the range of the machine and in which 'the amount and rate of the generating roll is alsoinfinitely variable within the range of the machine. Another object of the invention is to provide a machine of the character described and employ- 1 relative movements of alternate feed and with-.

drawal between the tool and blank are 'inter-' locked so that the generating roll does not begin until the tool mechanism is in operative position and the return roll for indeking does not com mence until the tool mechanism is in withdrawn or inoperative position.

Another object of the invention is to'provide a gear generating machine in which uniform and steady operation of the various moving parts may be obtained to the end that a smoother and better finish may be secured on the tooth surfaces of the gears to be generated.

Still another object of the invention is to provide a gear generating machine in which the generating roll and the relative movements between the tool and blank for alternate feed and withdrawal are hydraulically operated and interlocked.

A furtherobject of the invention is to provide a gear generating machine in which the rate of 10 generating and return rolls of the cradle can be separately varied at will and each within very wide limits.

Another object of the invention is to provide a gear generating machine employing reciprocating tools for producing the lengthwise tooth shape, in which provision is made for adjusting the tool mechanism and blank relative to one another so as to produce a relative rolling motion on the pitch line between the tool mechanism and the blank and thereby produce gears truly conjugate to a true crown gear.

Another object of the invention is to provide a generating machine of the indexing type in which the mechanism for producing the alternate movements of feed and withdrawal between the tool and blank for alternate cuttingv and indexing is employed, also, to effect relative separation of the tool ard blank to inoperative position after the gear has been completed and in which 36 this mechanism, for the purposeof this last named movement, is under the control or a manually-operable trip device.

Still another object of the invention is to provide a practical and efiicient type of machine for grinding straight bevel gears at high speed and in which a pair of rotating grinding wheels may be: employed to grind two tooth surfaces of a gear simultaneously by reciprocation of the rotating wheels in converging paths across the face of the gear. 7

The invention includes, also, various other 1111- ovements and refinements as will appearhereinaft'er from the specification and from the recital of the appended claims.

In the drawings: j Figure 1 is an end elevation of a straight bevel gear grinder built according to a preferred embodiment of this'invention, the view being taken looking at the work end of the'machine; Figure 2 is a plan view of this machine, parts being broken away to show the construction;

Figure 3 is also a plan view, but with the cradle and tool mechanism removed to show other con- 1 structional dr. tails 01' the machine; 55

. locking ofthe cradle and bed operating mechanisms is another feature making it possible to obtain higher production on this machinethan on machines of previous construction. Only that amount of roll need be used which is actually required to roll out the tooth profiles. The interlocking of the two mechanisms is a safety feature, also, preventing absolutely any possibility of indexing taking place while the grinding wheels are in operative position.)

Separate valves are provided to control the rates of roll of the cradle in opposite directions so that a high speed return can be obtained without sacrificing the slow generating roll required to secure that smoothness of tooth profile flnis which is sought in ground gears.

Once the machine is started, its operation is automatic, the parts performing their functions in proper sequence until the gear is completely ground. Then an automatic stop device is tripped tocause a valve to be shifted to close off the pressure line to the cradle piston,- thus stopping the cradle movements. I

.The distance to which the wheels are withdrawn periodically for indexing is limited by a movable stop-dog. Normally this stop-dog is held in operative position by a spring-pressed plunger. To take OK the completed gear and chuck a new blank greater clearance between the wheels and the work is ordinarily desirable. obtained by releasing the spring-pressed plunger referred to and allowing the piston that controls the bed-movement to bottom in its cylinder, thereby .withdrawing the wheels entirely clear of the work. b

No dressing mechanism has been shown for dressing the grinding wheels, and theymay be dressed by hand or through use of any suitable type of dressing mechanism. The operation of the machine and its principal features of improvement have been described generally. Reference will now be had to the accompanying drawings for a more detailed de- 28 which extend in a direction parallel to the axis of the cradle 25. These ways 28 may be hardened and ground and secured to the base 28 by screws 21, as shown in Figure 9. .28 designates a bed or carriage that is mounted on the'base 28 of the machine and is slidable on the ways 28. The tool mechanism is mounted on the bed 28 while the support for the work is secured to the cradle. The

tool end of the machine will be described first.

Mounted on the bed or carriage 28 for angular adjustment thereon is a supporting plate 88 (Figs.

7 s, c and 'n. This plate adjusts about a pivot pin 3| whose axis intersects the axis of the cradle. Adjustment of the plate 88 upon the carriage 28 is effected by rotation of the screw shaft 82 (Fig. 4). This shaft is joumaled in'a headed member 88, which swivels in the plate 88, and it is threaded into the head of -a stud 84 that swivels in the bed 28. The stud 84 is secured to the bed}! by the nut 88 which threadsonto thestem of thestud.

. The supporting plate 88 is secured in any position of its angular adjustment about theiaxis y of the head 8| .by T-bolts 38 (Figs. 5 and 8). which are secured in the bed '28 and have in engagement'with an arcuate hat 81 formed This can be the machine.

in theisunder surface of the plate 38 and curved about the axis of thepin 8| as a center;

There is an upright or column 48 (Fig. 7) mountedon the plate 38 and adjustable laterally thereon. Adjustment of this column on the plate 88 is effected by rotation of the screw-shaft 4|,

which is rotatably mounted in the plate 38 and which threads into the nut 42 carried by the column. The column is secured in any adjusted position bythe T-bolts 43 which are secured in 1 the plate 38 and have their heads in engagement with T-slots formed in the under-face of the column.

There are a pair of tool arms 45-mounted on the column 48 and adjustable angularly thereon about an axis a: which is offset from but parallel to theaxis of the cradle (Fig. 5). Each of the tool arms 45 is approximately right-angular in shape. One leg 48 of each tool arm (Figs 5 and 7) rests against one end face of the column 48. The other leg 47 of each tool arm extends at one side of the column 48 rearwardly from the leg 48.

The front leg 48 of'each tool arm. is grooved longitudinally to receive a pair of hardened V- shaped ways 48 (Fig. '7). The grooves in which these ways seat are so cut in each arm 45 each pair of ways is inclined to the end face of the column 48. This inclination is sufiicient to let the grinding wheels pass one another in their strokes across the face of the gear. There are a pair of tool slides 50 mounted to reciprocate on the tool arms. fllhese slides are formed with V-shaped grooves 5| at opposite sides and these grooves are adapted to cooperate with the hardened V-shaped ways 48 to receive the balls- 52 which form an anti-friction mounting for the slides 58, enabling the slides to be operated at high speeds. y

Each of the slides 58 is formed at one end with a dove-tailed guide 54 (Figs. 2, 5 and 6). Each guide extends from top to bottom of its slide and is inclined to the front face of the column in parallelism to the corresponding ways 48. There is a block 55 slidable on each way 54 and adjustable thereon by means of a screw shaft 58. There is a wheel head 58 mounted on each of the blocks 55. Each of these wheel heads is adjustable on its block in a direction at right angles to the direction of adjustment of the block on the associated guide 54.

The two grinding wheel spindles 88 are journaled on spaced anti-friction bearings 8| and 82 in the wheel heads 58. The grinding wheels W are secured to the two spindles 88 by nuts 84. Each wheel has a plane face 85 and a conical operating surface 88. Opposite side tooth surfaces of the gear to be ground are ground by the conical operating surfaces of the two wheels.

Adjustment of the blocks 55 on the guides 54 is for the purpose of spacing the operating surfaces of the wheels apart in accordance with the tooth thicknessof the gears to be ground. The two wheels operate preferably on opposite sides of the same tooth. Adjustment of the heads 88 on the blocks 55 is for the purpose of com- 5 pensating. for wear of the wheels. This latter adjustment is effected by rotation of the screw shafts 88 (Figs. 6 and 8).

Each screw shaft 88 is journaledin a guard- 88 that is secured in any suitable manner to or housing 88'. Rotatably mounted on each screw 15 shaft to is an arm 12. Mounted in the free end of each arm 12 is a spring-pressed plunger I9 whose inner end is shapedvas a pawl to engage the teeth. of the associated ratchet wheel II.

4 Each guard or housing 89 is closed by a coverplate 14 .that is secured in position by screws 15. There is a handle 19 secured to each the arms 12 and each handle extends outwardly through an arcuate slot I1 formed in the associated cover-plate". The slots II are curved about the axes of the screw-shafts 98. By graspsetting of a deflector 89. There is one of these deflectors 89 mountedin each of the housings 99 in proximity to the ratchet wheels and the defiectors are adjustable about the axis of the screw shaft 69 to govern the amount of feed on each movement of the handle 19. Each deflector is held in its adjusted'position by screws-II which pass through an arcuate slot 92 formed in the deflector and which thread into the associated housing 99. The slots 82 are curved about the axes of the respective screw shafts. 99. The

' wheel heads 59 are secured in any adjusted position by bolts 95 which pass through slots 99 in the respective wheel heads and thread into the associated blocks v55.

The two grinding wheels are driven by separate motors 99.. These motors are secured to blocks 9i that are adjustable rectilinearly on plates 92, the adjustment of the blocks 9I on the plates 92 being effected, in each case, by rotation of a screw shaft 99 that is journaled in a block 9I and threads into a plate 92. Each of the plates 92 is adjustably mounted on the-leg 41 of one of the tool arms 45. Adjustment of each plate 92 on the associated tool arm is in a direction at right angles to the direction of adjustment of the block 9| on the corresponding plate 92. Adjustment of the plates 92 is effected by rotation of the screw-shafts 95 which are 'journaled in the tool arms 45 and which thread into the plates 92. In their adjustments, the respective plates 92 move onways 99 formed on the outer faces of the sides 41 of the tool arms 45 and extending parallel to the direction of adjustment of the associated wheel heads 99.

The two grinding wheels W are driven fromthe pulleys 99 and 99 of each drive in alignment in any adjusted position of the associated grinding wheel head 59. I

The two tool arms 45 are adjustable angularly about the axis :2: to adjust theangle of conver: gence of the paths of reciprocating movement of the wheels in accordance with the angle of lengthwise convergence of the tooth surfaces to be ground. "This'adjustment is effected by rotation .-of the" screwshaft II9-"(Fig. 5)"which-threads into two heads III that are swivelly connected to studs .-III' which pass through arcuate slots I I9 in the flange I I6 of the column 49 and which thread into the tool arms 49. The sides 4'! of the tool arms are provided with lugs II4 (Figs. 6 and 7) which are joumaled on the cylindrical bar IIS and which rock on this her during the'de-i scribed angular adjustment of the tool arms. Thebar H5 is mounted in the upright 49 with its axis coinciding with the axis a: about which angular adjustment of the arms takes place. The arms 45 are also held on the column "by the gibs or straps II9. These straps II9'engage over lugs I29 formed integral with the respective tool arms and are secured to the column threaded into the column 49, thereby further securing the arms against movement after adjustment. Each of the toolv arms 49 is provided with an arcuate tongue I29 (Figs. 5 and 'I) that engages in an arcuate slot I29 in the face of the column 49, thereby to guide the arms in their adjustment on the column. The slot I29 is curvedabout the axis a: as a center.

The tool slides 59 are driven from the motor I25 AFlgs. 2 and 3) that is mounted upon the column 49; There is a bevel pinion I29 connected to the armature shaft of this motor. This pinion meshes with a bevel gear I2l that is secured to a'shaft I99 (Figs. 3 and 7) which is journaled in the column 49. There is a spur gear I9l secured to the shaft I99. This meshes with a spur gear .I92 which is secured to a shaft I99 that is also journaled-in the column 49. The

inner end of the shaft I99-is enlarged to form a crank-plate I94 (Figs. 5 and 7) There is a diametrical slot I95 extending across the crankplate and in this slot is mounted a block I99 which is adjustable therein by means of the screw I91. The block I96 carries the crank-pin or bolt I99. This crank pin or bolt serves to connect the crank arm I49 with the crank-plate.

The actuating member H9 is mounted for oscillation in a recess I4I formed in the front face of the column 49. There is'a shaft I42 formed integral with the actuating member II9 and extending rearwardly from the same. This shaft I42 is journaled in the column 49 with its axis coinciding with the axis at. There is an arm I44 keyed to the shaft I42 and held against axial movement thereon by the nut I45. There is a stud I49 mounted in. the free end of this am. There are a pair of opposed spring-pressed plungers I4lmounted in the free end 'of the crank arm I49. These plungers are adapted to engage thestud I49 to connect the crank arm I49 to the arm I44. The crank arm I49 can be readily disconnected from the arm I 44, however, by holding the arm I44 stationary and pulling the arm I49 away from the arm I44. The outer ends of the plungers I4l are tapered so that when this is done, they will be forced Japart readily. The

by the springs I49. i

The actuating member H9 is a double-armed member of a shape clearly shown, in Figure 5. Eacharm of this member is furcatedf to provide aslot I99. There is a block I9I mounted in each of the slots I99. Each of the blocks IiI is plungers are normally held in engagin positions g V 2,048,090 7 connected to one of the tool slides 50 by a pin I52.

The pins I52 pass through aligned slots I53 which are formed in each of the tool slides and in oval plates I54 that are seated in appropriately shaped recesses in these, slides. A nut I51 and washer I55 (Figs. 5 and 6) serves to secure each tool slide in any adjusted position relative to the actuating pin I52. The rear faces of the washers I55 are serrated to engage correspondingly serrated front faces of the plate I54, thereby the more firmly to connect the pins I52 andslides 50 together when the nuts I51 are tightened up.

Through the mechanism just described, the slides 50 are reciprocated simultaneously in opposite directions to cause the grinding wheels to grind the opposite side tooth surfaces of the gear. The work is mounted upon the cradle in a manner similar to that heretofore employed in gear generating machines of the segment-roll type, but will be briefly described here.

The gear to be ground Gis secured by any suitable chucking mechanism on a work spindle I60 (Fig. 2) that is journaled' in the work head I62. For gears of different cone distances, the work spindle may. be made directly adjustable in an axial direction in thework head or the work head itself may be mounted on the work head carrier for adjustment in a direction axial of the work spindle. For gears of different pitch cone angles, the work head carrier I63 is adjustable angularly on the cradle. The work head carrier isisecured in any adjusted position by T-bolts I64 whose heads engage in an arcuate T-slot I65. When the carriage 28 is in full depth position, the axis 1/ of the pin 3I passes through the center of the slot I65. I

The indexing mechanism may be of any suitable construction but preferablywill be of the notched-plate type and operated by the roll of the cradle, such an indexing mechanism being shown, for instance, in the U. S. patent of E. W. Bullock et al. No.- 1,679,809 of August '1, 1928. In the drawings of the present application, I61 designates the notched plate of such an index mechanism.

To grind the tooth profiles of a generated gear, the work spindle is rotated on its axis and simultaneously a motion is imparted to the cradle 25. The rotation 'of the work spindle is eifected by roll of the bevel gear segment I10 on the crown gear segment I12. The bevel gear segment I10 is adjustably secured by the bolts I13 to an arm I14 which is secured to a sleeve that is connected to the work spindle in known manner by the indexing mechanism, as shown, for instance, in the Bullock et al. patent above referred to. The crown gear segmentmay be made in two parts as shown in the Bullock et a]. patent, but preferably will be 01 the swinging type as disclosed in my Patent No. 1,780,350 of November 4, 1930. .The latter construction is shown in the drawings, the crown gear segment I12 being pivotally mounted by means of the pin I15 upon a bracket I16 (Figs. 1, 2 and 3) that is adiustably secured to the bed 20 of the machine by T-bolts I10.

In operation, the bed 28 is first moved'toward the cradle to feed the grinding wheels into depth, then the cradle is rolled in one directionto cause the blank to be rolled past the grinding wheels, then the bed is withdrawn to withdraw the wheels from engagement with the work, then the cradle .is returnedto initial position, the blank being indexed o e return roll and then the cycle bes ns e erg The mechanism for imparting the alternate movements of feed and withdrawal to the carriage 28 will now be described.

Suitably mounted in the base or frame of the machine is a casting I (Figs. 3, 11 and 12) that is bored to receive the cylinder I8I. The piston 5 I82 reciprocates in this cylinder. This pistonv is connected by the nut I83 with a piston-rod I84. The piston rod I84 extends outwardly from the cylinder through-a packing-box I85 of suitable construction which is mounted in the end plate 10 I86 of the cylinder. The end plate I86 is held in position by bolts I81. I a

Externally of the cylinder, the piston-rod I84 is connected to a rack I88 (Figs. 3, 9 and 10). This rack slides in a groove formed in a coverplate I89 that is secured to the frame 20. The rack is held in position by straps I90. The. rack meshes with a spur gear I92 which is secured to a shaft I93 that is suitably journaled in the base of the machine. There is a spur gear I94 se- 20 cured to the shaft I93. This spur gear meshes with. a spur gear I95 that, in-turn, meshes with a spur gear I96. The two gears I95 and I96 are mounted on suitable studs in the base of the machine. The gear I96 meshes with a rack I 91 25 that is secured to the under-face of the carriage 28. As the piston I82 reciprocates in the cylinder I8I, then, a reoiprocatory movement will be imparted to the bed 28.

Oscillation of the cradle 25 is effected by re- 30 ciprocation of a piston 200 (Figs. 12 and '13). This piston slides in a cylinder 20I' which is mounted in a bore of a casting 202. The cylinder I8I is horizontal, but the cylinder 20l is positioned diagonally in the base of the machine, as clearly 35- shown in Figure 1. v

Thereis a piston-rod 204 secured tothe piston 200 by the nut 205. This piston-rod 204 extends upwardly through the stuffing-box 206 that is provided in the upper end-plate 201 of the cylinder 20I. The cap 208 of the stuiilng-box is secured in place by screws 209 (Fig; 11) There is aneared-head 2l0 secured by a pressed fit to the upper end of the piston rod 204. This head is connected to a link 2I3 which is, in turn, connected to the cradle 25'by the pin 2 (Fig. 1).

A cylindrical guide or sleeve 2 is provided for the sake of rigidity to guide the head 2I0 throughout its movement. .The head 2I0 slides in the bore of this guide or sleeve 2| 4. The guide 2 is secured to the casting 202 by bolts 2l5 and the sleeve 2I4 is formed at one side with an integral extension 2I1 which is bolted to the casting I80 by bolts 2I8. The extension 2I1 is shaped to form the inner end wall of the cylinder I8I and there is a stop-member 2I9 secured in this extension 2I1 and extending into the chamber of the cylinder I8I to provide a stoplimiting movement of the piston I92 inone direction. The movement of the piston I82 in 60 the opposite direction is normally limited by a stop-dog 220 (Figs. 3 and 10).

This dog is pivotally mounted by means of the pin 22I in the of the rack I88, the hooked end of the stop-dog engaging in a suitable shaped recess 222 formed in the-end face of the rack.

The stop-dog 220 is normally held in operative position by a spring-pressed plunger 224 whose 70 head 2251s so shaped, as clearly shown in Figure 10, to have surface contact with the back of the stop-dog 220 when the latter is in operative position. The plunger 224 is normally urged into operative position by the coil-spring 220 which (5 surrounds the plunger and which is interposed between the head 225 of the plunger and one end wall of a recess 221 in the cover-plate I89 in which the head 225 of the plunger slides. The head 225 of the plunger can be retracted from operative position, for a purpose hereinafter to be described, by pulling on the knob 228 which is threaded on the outer end of the plunger. downward rocking movement of the stop-dog 228 is limited by a lug 229 which is formed integral with the cover-plate I89 and which is adapted to contact the tail of the stop-dog. Access to the plunger and stop-dog can be had by removing the auxiliary cover-plate 238 which is secured to the cover -plate I89 by screws (not shown).

The movements of the pistons I82 and 288, that is, the movements of the bed 28 and-cradle 25, respectively, are controlled, respectively, by two valves 235 and 238 (Figs. 11 and 19). These valves are mounted in alignment to slidein an elongated sleeve 238 that has a pressed'fit in a bore in the casting I88. The two valves are movable relative to one another but are resiliently connected together by the rod 239 and spring 248. The rod 239 is pinned to the valve 235 and slides in the bore of the valve.238. The spring 248 surrounds the rod 239 and seats in a recess formed in the outer end of 'the valve 238. The spring is interposed between the end wall of this recess 24I and the head 242 which is pinned to the outer end of the rod 239. The two valves 235 and 236 are moved relative to one another by application of fluid pressure between the adjacent There is a plate245 (Figs. 3, 13 and 14) rigidly connected to the head 2I8 of the piston rod 284- bya pin 248. This plate 245 is T-shaped in cross-section and slides in a correspondingly shaped groove 241 in the sleeve 2I4, as the piston 288 reciprocates in the cylinder 28I. T-slot 248 out longitudinally in the plate245 and the front face of the plate is serrated at both sides of this T-slot as clearly shown in Figures 13 and 14. 258 and 25I designate, respectively, a pair of stops or dogs that are 'adjustably secured to the plate 245 by T-bolts 252 whose heads engage in the T-slot 248. The under surfaces of these dogs 258 and 25I are serrated to intermesh with the serrations of the plate 245 to hold the dogs securely in any position of adjustment on the plate.

As the piston 288 moves back and forth in the cylinder 28I, the dogs 258 and 25.I are brought alternately into engagement with a lug 255 (Figs. 14 and 11) that is secured by screws 251 to one arm of a bell-crank member 258. The bell-crank member 258 is pinned toa shaft 258 that is journaled in the casting 2I4 and held against axial movement therein by the washer 259 which is The There is a pinned to the shaft 258. The bell-crank member valve inwardly is limited by engagement of the collar 265 formed on the valve stem; with the cap 284,-while movement of the valve'outwardly is inder.

limited by engagement of the valve Itself with this same cap 284.

To 'make the movement of the valve 235, when shifted, sharp, and as nearly instantaneous as possible, a load and fire mechanism is provided.

Thus, there is a spring-pressed plunger 281 mounted in a pocket 288 in the casting I88 and having a V-shaped outer end to engage a V- shaped lug 289 that is formed integral with the bell-crank member 258. The plunger 281 is pressed outwardly by the coil-spring 218 which surrounds the stem of the plunger and is interposed between the end wall of the pocket 258 and the head of the plunger. As soon as the bellcrank member 258 has been moved past center in one direction or the other by the dog 258 orthe dog 25I,' as the case may be, the load and fire mechanism'operates quickly throwing the bellcrank member on to the limit of its movement, thereby quickly shifting the valve 235.

The pressure fluid for actuating the hydrauli cally operated parts of the machineis pumped from a sump provided in the base of the machine. The pressure pump may be of any suitable construction and is not shown except diagrammatically inFigure 19, where it is designated at 215.

'The pump is driven by a motor 216 which is suit-v ably mounted on one side of the frame of the machine (Figs. 2 and 3). A pipe-line 211 conducts the pressure fluid from the pump 215 to the duct 218 in the casting I88 (Fig. 12) the final section of the pipe line 211 threading into a cover-plate 219 that is secured to the casting I88.

288 and 28I, respectively, that surround the cylinder 'I8I and lead, respectively, to the ports 282 and 283 in the sleeve 238 (Figs. 11 and 19) Both the ports 282 and 283 are arranged radially ,The duct 218 communicates at its ends with ducts aroundthe sleeve 238 and the ducts 288 and 28I 1 respectively, surround the sleeve at spaced points alongits length to communicate with the ports, respectively. A relief valve 285 is connected to the line 211 by a line 288 (Fig. 19) This relief valve may be of any suitable construction and is intended to prevent building up of pressure in the system beyond a desirable limit.

The motive fluid is exhausted from the sleeve 238 throughtwo sets ofradially arranged ports designated at 298 and 29I, respectively. The ports 298 communicate with a pipe 292. The ports 2!" communicate with a pipe 293, the two pipes 292 and 293 are connected together by a pipe 294- which leads back to the sump of the machine. There is a globe-valve 295 connected into the pipe-line 293. This valve may be of any known or suitable construction and is adjustable to control the rate of movement of the carriage 28, as will appear hereinafter.

On one side of the piston I82, the cylinder I8I is connected with the sleeve 238 through the ports 291 (Figs. 11, 12 and 19). These ports 291 lead into a duct 298 that surrounds the cylinder I8I. The duct 298 communicates with a duct 299 that extends longitudinally of the cylinder I81 and leads into a duct 388. The duct 388 communifi cates with a duct or groove 38I that surrounds the sleeve 238 and has communication with the interior of the sleeve, 238 through the radial ports 382 provided in this sleeve.

On the other side of the'piston I82, the-cylinder I8I is connected to the chamber in the sleeve 238 through the ports 385 in the wall of the cyl- These ports 385 communicate with a groove or duct 388 that surrounds the cylinder |8I and leads into-a-duct 381 (Figs. 11 and 15).

This duct 301 communicates with a cylindrical groove or duct 308 that surrounds the sleeve 238. The duct 301 connects with the chamber of the sleeve 238 through the radially arranged ports 309 in the sleeve. The groove 308 leads into a duct 3l0, which extends longitudinally of the sleeve 238. There is a duct 31! leading from the duct 3I0 and extending parallel to the duct 301. The duct 3 communicates with the radially arranged ports 3|2 in the sleeve 238.

The connections between the sleeve 238 and the cylinder 20! will now be described. There are a-series of radially arranged ports 3I5 cut in the sleeve 238 near the outer end thereof." These ports communicate with a duct 3l6 that surrounds the sleeve 238 and leads into duct 3|1 that extends longitudinally of the sleeve. The duct 3|1 also communicates with the interior of the sleeve through the duct M8 and the ports 3) which lead from this latter duct and are formed in the sleeve 238. There is a. pipe-line 320 leading from the duct 311 to the ports 364 (Figs. 12 and 18)-of a sleeve 365 that is mounted in a suitable bore in the casting 202 and is threaded into this bore.

There is a tapered'valve 366 mounted in the bore of the sleeve 365 and adapted to rest upon a correspondingly shaped seat formed in the bore of this sleeve. This valve 366 controls the amount of flow of the motive fluid between the pipe 320 and the duct 368. The latter duct com-- municates with'the ports-369 in the sleeve 365 and also communicates with the ports 310 in the generating cylinder 20! (Figs. 12, 17 and 19).

The amount of opening of the valve 366 is controlled by adjustment of a rod 312 (Fig. 18) which threads into a nipple 313 that is secured to the lower end of the sleeve 365. The rod 312 extends through a packing-box 314 that is held in place in the sleeve 365 by the nipple 313 and the rod 312 contacts at its upper end with the bottom face of the valve 366. There is a cap-member 315 secured to the rod 312. The periphery of this cap member315 is graduated at its upper edge so as to permit accurate adjustment of the amount of opening of the valve 366. When the line 320 is on pressure, the valve 366 is fully open, but when the line or duct 368 is on exhaust, the valve is pressed down on to its seat and is only open so far as is permitted by the adjustment of the rod 312; Thus, the rate of exhaust from the upper end of the cylinder 20| .is controlled to control the rate of movement of the piston 200 upwardly. There is a guide member 311 threaded into the upper end of the sleeve 365. This member is bored as indicated at 318 to receive the stem 319 of the valve 366 and guide the valve in its movements.

The sleeve 238 is connected with the cylinder 20l on the lower side of the piston 200 through the ports 360 (Figs. 11 and 19) in the/sleeve. These ports communicate with a cylindrical groove or duct 36! in the casting I80 that surrounds the sleeve 238. There is a pipe-line 362 leading from the duct 361. This pipe-line communicates with a groove or duct 322 (Fig; 17) formed in the casting 202 and surrounding the valve-sleeve 323 that has a pressed fit in a suitablev bore in this casting. There is a slidable valve mounted in the sleeve 32: and reciprocable therein.

The valve 325 is shaped as clearly shown in Figure 17. It is normally pressed upwardly by a coil-spring 326 which is seated in a recess in the bottom of the valve and is interposed between dicated diagrammatically in Figure 19).

the top wall of the recess 321 and the inside face of a nut 328 that threads into the sleeve 323. The valve 325 is held in the depressed position shown in the drawings, during grinding of a gear, by action of a solenoid 330 (shown in Fig. 16 and in-.

The core bar of this solenoid is pivotally connected to a lever 332 which is pivotally mounted on the casting 202 and which is pivotally connectedto the stem 333 of the valve 325. The stud 334 serves as a pivot for the lever 332 while it is pinned at opposite ends to the valve stem "333 and to the core-bar 335 of the solenoid.

The solenoid 330 is connected by'the lines 331 and 338 (Fig. 19) with an automatic stop mechanism 333 that may be of any suitable construction and that, in turn, is so connected to a source of electrical power that the solenoid is energized during the grinding of a gear. When the last tooth of the gear has been ground, the stop mechanism is tripped, as will hereinafter be more fully 1 described, breaking the connection to the solenoid releasing the core-bar 335 and allowing the valve 325 to be shifted from its lowermost position upwardly by action of the spring 326.

When the valve 325 is in the position shown in Figures 1'1 and 19, the motive fluid can fiow from the duct 322 through the ports 340 in the sleeve 323 into the chamber of the valve 325. Thence,

344 is tapered and a correspondingly tapered seat 348 is provided for the valve in the parti-' tion wall 341.

When the valve is open, the motive fluid flows I from the duct 342 into the duct 346. The latter duct leads into a duct 350 (Figs. 12 and 1'7) that communicates with a duct 351 which surrounds the cylinder 20l and communicates with the cyl. inder through the ports 352 in the cylinder wall. The valve 344 is mounted to slide on a rod 354 which threads into a nut 355 and which extends upwardly along side the sleeve 214, being supported and guided at its upper end by a bracket 356 which is secured to one side of the sleeve 2. The valve 344 is adapted to rest on a disc 358' which is pinned to the lower end of the rod 354.

rate of erl aust through this duct, that is, the rate of down-roll oi the cradle, is controlled by the amount of opening of the valve 344 which is adjustable as just described.

Besidesthe series of ports 281 and 305 in the cylinder l8l, there is another series of ports 380 out radially in thiscylinder, (Figs. 11 and 19). These ports 380 communicate with a groove or duct .38l that surrounds the cylinder m and leads into a duct 382. -The duct 382 communicates with a duct 383 that surrounds the cylinder |8l (Figs. 11,12 and 19) and leads intoaduct it from between the valves 238 and 238.

at a point to admit the pressure fluid or exhaust 7 When the pressure fluid is admitted between the valves, the two valves are spread apart. When-the motive fluid is exhausted from between the valves, they are forced together again by the action of the spring 248. 4

There are a series of radially arranged cuts 388 drilled in the piston I82 (Figs. 11 and 12). 3 These communicate with ports 389 drilled in the piston rod I84. The piston rod I84 is hollow, providing a duct 398 that is connected-by the flexible hose 392 with the line 294 which leads back to th sump of the machine.

In use, the various adjustable parts of the machine are adjusted as appropriate for the gear which is tobe ground.' Thus the arms 48 are adjusted angularly on the column 48 in accordance with the angle of convergence of the sides of the teeth of the bevel gear to be ground and the plates 88-are adjusted on the slides 88 in accordance with the thickness of the teeth to be ground. Also, the slides 88 are adjusted longitudinally on the arms 48 and the column 48' is adjusted laterally on the supporting plate 38 as determined by the cone-distance of the gear to be ground. The throw of the crank I34 is adjusted in accordance with the face width of the gear to be ground. The'supporting-plate 88 is adjusted angularly on the bed or carriage -28 in accordance with the dedendum angle of the gear to be ground if it is desired that this gear be ground conjugate to a, true crown gear. If the gear is to be ground, however, conjugate to a nominal crown gear, the supporting plate 38 is set at zero. The work head is adjusted on the work head carrier to adjust the gear to the correct cone distance and the work head carrier is adjusted angularly on the cradle in accordance.

- a distance apart determined. by the amount of lation' of the handles I8 roll which it is desired to impart to the cradle. The grinding wheels are dressed in accordance with the pressure angles of the side tooth surfaces to be ground'on the gear. They are also adjusted that when in full depth position, their tips will operate in the root plane of the gear.

This last adjustment is effected by rotation of the screws 8F 6 and 8) through manipu- The valves 344 and 386 (Figs. 12 and 18) are also adjusted by rotation of the rods 384 and 312-, respectively, to control the rates of roll of the cradle in opposite directions. The valve 295 is adjusted to control the rate of movement of the carriage-- 28. When all of the adjustments have been made, the machine is started. At this time, the bed 28 is in full withdrawn position. .The first movement is an idle up-roll of the cradle as will hereinafter be morefuliy described. Then the feed movement begins. The bed 28 moves inwardly, carrying the wheels into depth. When full depth position is reached, the down-roll of the cradle begins. In this movement of the cradle, the profiles of :a pair of toothsurfaces of the gear are 5 rolled across' the rotating and reciprocating grinding wheels. Atthe end of the down-roll,

same.

two'tooth proflles will have been fully ground. Then the cradle stops and the withdrawal movement ofthe carriage 28 begins. This withdrawal movement carries the wheels clear of the gear. When the wheels are clear, the carriage-movement is, stopped and the up-roll of the cradle begins. During the up-roll, the work is indexed. At the end of the up-roll, the cradle is again stopped and the cycle begins anew with the grinding wheels fed into the gear so as to grind a new pair of tooth surfaces.

The valves 238 and 238 and the pistons I82 and 288 are shown in Figures 11, 12 and 19 in the positions which they occupy when the care riage 28 has'almost finished a withdrawal movement, while inFigure 13 the piston 288 is shown in the position which it occupies at the end of the indexing up-roll of the cradle.

I shalldescribe the sequence of operatic beginning with the positions of the parts shown in Figures 11, 12 and 19. At this time, the cradle is stationary in its lowermost position for with the valve 238 occupying the position shown in the drawings, flow of the pressure fluid to the lower end of the cylinder 28I is shut offand dischargelof the exhaust'fluid from the upper end of the cylinder 28I is shut off. The piston I82 is, however, being forced to the left in Figures 11 and 19 in its withdrawal movement for the pressure fluid is flowing from the ports 283 in: the sleeve 238 through the ports 312 in this sleeve, the ducts 3H and 3I8 and around the valve 238 through the duct 381 and through the ports 388 into the cylinder I8I at the right end of the During the movement of the piston I82 3 to the left, fluid exhausts from the left end of the cylinder I 8I through the ports 291, the ducts. 298, 288, 388 and 38I, the ports 382 and 29I in the sleeve 238, and the lines 293 and 294 back to the sump, the rate of movement of the piston I82 being determined by the setting of the globevalve 288.

, Toward the end of its leftward movement, the piston I 82 will clear the ports 388 in the cylinder I 8|, allowing the pressure-fluid to flow from the ports 388 through the' ports 388. in Figures 11, '12 and 19, the piston I82 is shown just at the point where it is beginning to clear the ports 388. Assoon as the ports 388 begin to open, the pressure fluid flows through the ducts 38!, 382,383 and 384, and the ports 388 in the sleeve 238 in between the valves 238 and 238. Since the spring 248 is compressible by relative movement between the valves'238 and 238 and since the valve 238-is held in its left position shown in Figures 11 and 19 by the spring 248 (Figs. 14 and 11), the pressure fluid forces the valve 238 further to the left from the position shown in these flgures an against the resistance of the spring 248.

Just before the valve 238 will have moved fully to the left, the leftward movement of the piston I82 will be stopped by engagement of the stopdog228 (Fig. 10) with the rack I88. In its movement to the left, the valve 238 will open the ports -3I8 and 388 of the valve-sleeve 238.

and'f19) and the ports 348 into the chamber of thevalve 328. Thence, the pressure v fluid flows 7 through c ports 3 into the duct 342 (Figures 7 12,16, Hand 19). The pressure of the motive fluid Opens the valve 344 fully, the valve sliding upwardly on the rod 384. The pressure fluid flows, then, through the open valve into the duct 348 whence it flows through the ducts 388 and 35l and the ports as: into the-lower end of the cylinder 20I to force the piston 200 upwardly in this cylinder to effect the indexing up-roll of the lcradle. At this time, fluid is exhausted from the I upper end of the cylinder 20I through .the ports 310, the duct 368 and the ports 369 (Figs. 12, 18 and 19) into the sleeve 365 which houses the valve 366. The rate of flow of the exhaust fluid between the valve 366 and its seat 361 is determined by the adjustment of the rod 312 made when setting-up the machine. The exhaust fluid flows through the valve from the ports 369 to the ports 364 whence it returns through the line Y 320, the duct 3I6 (Figs. -11 and 19) the ports 3I5 and 299 in the sleeve 238, and the lines 292 and 294 back to the sump.

During the up-roll of the cradle, the index mechanism is operated, being tripped and actuated by the roll of the segment I10 on the crown 20. gear segment I12, as in the index mechanism of" the Bullock et a1. patent above mentioned and commonly in index mechanisms of the notched *plate type such" as used on various bevel gear cutting and grinding machines well known in the 5 ar Toward the end of the up-roll of the cradle, the dog I carried by the plate 245 engages the lug 255 carried by the projecting arm of the bellcrank 256 and as the piston 200 bottoms in the cylinder 20I (Fig. 13), the bell-crank is rocked upwardly, swinging the lug 269 (Fig. 14) past center and through action of the load and fire mechanism shifting the valve 235 from the position shown in Figures 11 and 19 to the position shown in Figure 14. The ports 302 (Figs. 11 and 19) are now put on supplyfromthe' ports 283 and the pressure fluid flows from the ports 382 through the ducts 30I,308, 299 and. 298, and the ports 291 into'the left end of the cylinder 0 I81. This forces the piston I82 toward the right in the cylinder to move the bed 28 inwardly through operation of the rack I88 and gears I92, I94, I95, I96 and rack I91 (Fig. 9) to feed the rinding wheels into depth. During this movement, fluid exhausts from the right end of the the cylinder I'8I through the ports 305, the duct 301, ports sea and 29I, and the lines 293' and 294 back to the sump. As before, the rate of movement of the piston I82 is. determined'by the setting of the glode-valve 295.

At this' time, as described, the valve 235 is at the right limit ofits movement in the sleeve 238, occupying the position shown in Figure 14. During the first part of the movement of the piston 55 I82 to the right, part of the fluid between the -va'lves'235 and 236 is exhausted, flowing through the ports 386, the ducts 384, 383, 382, 38I and ports 380 into the cylinder I8I whence it flows back to the stump through the ports 305. As the 60 fluid exhausts from between thevalves 235 and 236, the valve 236 shifts to the right under actuation of the spring 249. Before the valve 238 has shifted fully over-to the right, however, the ports 380 are shut 011' by the piston I82 in its 05 movement to the right. But the piston I82 again v clears the ports 380 just before the piston I82 reaches the end of. its reedfz'itovement to the right and the remainder of the fluid between the valves 235 and 236 is allowed to exhaust from between 70 the valves 235 and 236 through the ports 336,

ducts 384. 383,382, and 38I,- the ports 380 in the cylinder IN, the ducts 388 in the piston I82, the ports 389 in the piston-rod I84, the duct 390 in this piston-rod, and the hose 3.92 to the pipe 75 294, returning thence to the sump. The valve 236 is, therefore, shiftedfully over to the right by action of the spring 240 to abut against the valve 235 which is already, as described, fully over to the right. The inward feed movement of the piston I82 is stopped by abutment of the 5 piston. rod I84 against the positive-stop 2I9 (Fig. 12).

with the valve 236 fully over to the right, the pressure fluid flows from the ports 282 in the sleeve 238 through the ports 3I9 in this sleeve, the ducts 3I8 and 3", the line 320 (Figs. 11, 14, 18 and 19), and the ports 364 into the chamber of the valve 366. This valve will be forced fully open by the pressure of the pressure fluid. Thus the pressure fluid will be free to flow through 15 the ports 369 in the sleeve 365, the duct 388, and the ports 310 in to the upper end of the cylinder 20I, forcing the piston 200 downwardly in this cylinder to rock the cradle downwardly to produce the generating roll. At this time, fluid ex- 20 hausts from the lower end of the cylinder 20I through the ports 352 the ducts'35l, 350 and 346, through the opening between the valve 344 and its seat 348, through the duct 342 (Figs. 14, 17 and 19), the ports 34I and 340 in the sleeve. 323, 25 me line 362, ports 360 and 290 in the sleeve 238 (Figs. 11 and 19), the lines 292 and 294 to the sump. The rate of down roll of the cradle 25 is determined by the setting of the valve 344.

During the whole of the down-roll of the cradle, 30

the carriage 28 is stationary, the piston I82 being held against the positive stop 2| 9 (Fig.11), by pressure of the motive fluid on the left end .01 this piston. 7

By appropriate setting of the rods 312 and 354 (Figs. 18 and 12), the movement of the generating piston 200 can be controlled so that the cradle will have a slow generating downroll and a comparatively rapid return roll. 7

Just before the end of the down-roll of the 40 cradle, the dog 250 strikes the lug 255 carried by the projecting arm of the bell-crank 256 (Figs. 14 and 19) and as the piston 200 moves to the limit of its downward movement, the bellcrank 256 is rocked througn operation of the dog 250:.and the load and flre mechanism, from the position shown in Figure 14, shifting the valve 235 to the left to the position shown in Figures 11 and 19. In this movement of the valve 235, the valve 236- is also carried to the left without compressing the spring 240 for the two valves at this time are in abutting engagement. v, The movement of the valve 236 to the left stops the movement of the cradle for the ports.3I5,-,3 60 and 3I9 are all shut off and the motive fluid'neither flows to nor exhausts from theeylinder 20I. v

The movement of the valve 235 to the left, however, puts the right end of the cylinder I8I on supply, the pressure fluid flowing from the ports 283 to the ports 3I2,'the ducts 3I I, 3l0 and 301, and the ports 305 .into the right end of the cylinder I8I. Thus, the carriage 28 is moved rearwardly to withdraw the grinding wheels from engagement with the gear being ground. At this time, the fluid exhausts from the left end of. the

cylinder III-through the ports 291, the ducts 298, 299, 300, 30I, the parts 302 and 29I and thelines 293 and 294- to the sump. As the piston- I82 moves to the left, it opens. the ports 380, supplying pressure fluid through theducts SM,

382, 383 and-384, andthe ports 386 between the valves 235 and 236 to causethe valve 236 to be separated from the valve 235 and moved further to theleft against the resistance of the spring m. The piston I82 is shown'in Figures 11 and 

